Adjusting the viscosity of polyalkenamers

ABSTRACT

The molecular weight of cycloolefin polymers is adjusted by effecting the catalytic polymerization of cycloolefins in organic solvents in the presence of from 0.001 to 1 percent of an 1olefin.

' United States Patent Nutzel et al. [451 Aug. 15, 1972 [54] ADJUSTINGTHE VISCOSITY OF 3,449,310 6/1969 DallAsta et al. ..260/93.lPOLYALKENAMERS 3,458,489 7/1969 Natta et al. ..260/93.l 72 I t 2 Karl l3,459,725 8/1969 Natta et al. ..260/93.1 1 Hm 32: fifig 3,476,72811/1969 Natta et al. ..260/93.1 Leverkusen all Germany 3,385,840 5/1968Natta et al. ..260/88.2 R 3,598,796 8/1971 Nutzel et al ..260/88.2 R[73] Assngnee: Farbenlabriken Bayer Aktiengesellschaft, Levcrkusen,Germany [22] Filed: 1970 Primary Examiner-Joseph L. Schofer [21] Appl.No.: 26,154 Assistant Examiner-Richard A. Gaither Attorney-Connolly andHutz [30] Foreign Application Priority Data April 15, 1969 Germany ..Pl9 19 047.7 7

'I'RA T [52] US. Cl ..260/80.78, 260/882 R, 260/93.l [57] ABS C 511111.01 ..cosr 17/00, C08f 15/02, C08f 3/02 Th molecular w g of y q -pym [58] Field of Search ..260/93.l, 88.2 R, 80.78 iusted y g thecatalytlq polymerlzatwn of cycloolefins in organic solvents 1n thepresence of [56] References Cited from 0.001 to 1 percent of anl-olefin.

UNITED STATES PATENTS v 7 5 Claims, No Drawings ADJUSTING THE VISCOSITYOF POLYALKENAMERS The ring-opening polymerization of cyclo-olefins suchas cyclobutene, cyclopentene, cycloheptene, cyclooctene, cyclodecene andcyclododecene is known. It is standard practice to use organometallicmixed catalysts containing compounds of tungsten, molybdenum, tantalum,niobium or titanium. It is, however, only possible to obtain acommercially workable economic process by using co-catalysts. Compoundscontaining a --O-, OH or SI-I group in the molecule, aromatic andaliphatic nitro compounds and epoxides are active as co-catalysts.Moreover, pure starting compounds of the kind required for reproduciblepolymerization reactions, provide polymers having undesirably highviscosities, and as a result the polymers cannot satisfactorily beprocessed, either in internal mixers or on roll stands, even at elevatedtemperatures.

The present invention relates to a process for the ring-openingpolymerization of cycloolefins with organometallic mixed catalysts in aninert organic solvent, in which an l-olefin is added to the cyclo-olefinin a quantity of from 0.001 to percent by weight.

In the context of this invention, cyclo-olefins include in particularthose containing from four to 12 carbon atoms, such as cyclobutene,cycloheptene, cyclo-octene, cyclononene, cyclodecene, cycloundecene andcyclododecene; and also substituted cycloalkenes whose substitutents arenot situated on the double bonds, for example 3- and4-methyl-cyclopentene. Cyclopentene is preferred. The cyclo-olefins maybe polymerized either alone or with up to 30 percent by weight, andpreferably with from 0.05 to 5 percent by weight, of a bicyclic orpolycyclic olefin, such as dicyclopentadiene, norbornadiene ornorbornene.

l-olefins are olefmically-unsaturated compounds containing terminaldouble bonds, such as ethylene, propylene, l-butene, l-pentene,4-methyl-l-pentene, styrene and others. They are added to thecyclo-olefin during polymerization in quantities of from 0.0010 to 5percent by weight, and preferably in quantities of from 0.01 to 1percent by weight.

The viscosity of the polymers can be adjusted by the addition, accordingto the invention, of l-olefins in the quantities specified without anyappreciable changes in their microstructure (for example in the cisortransbond content or the polymerization velocity).

For large-scale operation, the polymerization of cycloalkenes is bestcarried out in. solvents only. To this end, polymerization is carriedout by dissolving a cycloalkene, preferably cyclopentene, in an inerthydrocarbon such as hexane, cyclohexane, benzene or preferably toluene.The concentration of the cycloalkene should be from 5 to 25 percent byweight and preferably from to 20 percent by weight. The lolefin is addedto this mixture, either as such or in solution in the particularsolvent. As a rule, this is followed by addition of the co-catalyst, theheavy metal compound and finally the organometallic compound. Althoughthe order can be changed, the organometallic component is usually addedlast of all.

I. a. Compounds of metals of groups IVa, Va and Vla of the periodicsystem, such as TiCl TaCl NbCl, WCL, WOCl WCI,(OR) MoCl, and W(allyl) b.compounds of metals of groups I to IV of the periodic system,corresponding to the formula R ,R ,,R ,Me

in which R represents a C -C hydrocarbon radical,

R represents a halogen atom,

R represents a hydrogen atom,

Me represents a metal atom, preferably Mg, Al or Sn x, y, 2 can be anynumber from 0 to 4 although x +y 2 can only have the maximum valency ofthe cor responding metal and y is always lower by at least one unit thanthe maximum valency.

Examples of co-catalyst systems of type I are 2H5) c s fl e a 6 4 9)2!L/ w'E and s/ s )3- II. a. An organic compound including a complexcompound of a metal of groups lVa-Vlla of the periodic system which inaddition to the organic radical may also contain halogen or hydrogen.

b. A compound acting like a Friedel-Crafts catalyst.

Examples of cowatalyst systems of type II are s s)2/wC s, W( y BFm, 3[ 65)6] a, y )4/ 4 3[ 6 5)6] I OCIm 4 9)2/W 6, N 3[ 6 5)6] 3 n 4H9) 2/1.aCl

The catalyst combinations may be used in quantities of, for example,from 0.1 to 5 percent by weight, based on monomer. The quantitativeratios in which the individual components are used may vary within widelimits, for example from a b 0.1 5 to 5 0.1 (based on weight). The mostfavorable ratio must be determined beforehand for each combination.

It is preferred to operate with pure, dry reagents in a protective gasatmosphere of ultra-pure nitrogen or pure noble gas such as argon, inorder to obtain reproducible results. The protective gas atmosphere isgiven a slight excess pressure (approximately 0.2 atrns.) in order toprevent the penetration of air. Higher pressures do not have any adverseeffects. Polymerization is usually carried out at a temperature of from-30 to +30 C. and preferably at a temperature of from --1 5 C. to +15 C.

On completion of the reaction, the catalyst is deactivated, convenientlywith approximately 5 percent by weight (based on monomer) of aproton-active compound, such as formic acid or methanol.

It is advisable simultaneously to add a complexformer, which preventsthe metals from remaining in the polymer after processing. Diamines suchas ethylene diamine, aminoalcohols such as ethanolarnine, or hydroxyacids such as tartaric acid, may be used for this purpose.

The polymers may be isolated by precipitation in three to five times thequantity of a solution of a lower alcohol, 1 percent by weight (based onalcohol) of an anti-ager such as di-tert.-butyl cresol, or B-phenylnaphthylamine being dissolved before precipitation. It is also possible,however, to remove the solvent by introduction into boiling water. Inthis instance it is desirable to introduce from 0.1 to 0.7 percent byweight, based on polymer, of an anti-ager together with the stopper.

The residual moisture can be removed by means of a recirculating-airoven, a belt-type dryer or a drying screw.

it is of course also possible to carry out the process as a whole in acontinuous cycle.

Pure dry reagents and apparatus and a protective gas atmosphere ofultra-pure nitrogen are used in each of the following examples. Theparts and percentages indicated are parts and percentages by weight.

COMPARISON EXAMPLE 1,000 parts of toluene and 200 parts of cyclopenteneare introduced into a 2 literautoclave equipped with a glandlessstirrer, thermometer and ultra-pure nitrogen inlet. 1 mMol of WC]dissolved in 20 parts of toluene is introduced at room temperature inthe absence of air followed by the addition of 0.5 mMol of2-cyclopentenyl hydroperoxide in the form of a 5 percent solution incyclopentene. Cooling to 1 C. is followed by the addition of 1.32 mMolsof aluminum triisobutyl in solution in 10 parts of toluene. The externaltemperature is kept at from 0 to C. by external cooling. After 4 hours,polymerization is stopped by the addition of parts of ethanolamine andthe polymer is precipitated in 4,000 parts of methanol containing 20parts of 4- methyl-2,5-di-tert.-butylphenol, after which it is dried ina recirculating air oven at 80 C.

The yield comprises 58 percent of the theoretical, while the trans-bondcontent is 93.2 percent. The product has a Mooney viscosity in excess of150 ML/4.

EXAMPLES 2 to 5 Cyclopentene is polymerized and the resulting polymer isworked up as described in example 1, except that increasing quantitiesof l-pentene are added before the WCI The quantities of l-pentene, theMooney ML-4 values, the yields and trans-bond contents are set out inthe following table.

Cyclopentene is polymerized and the resulting polymer is worked up asdescribed in example 1, except that increasing quantities of l-butenedissolved in toluene (1 percent by weight) are added before the WCI Thedata set out in the following table provide some indication as to theregulating effect k of l-butene Mooney- Yield trans-bond based on valveof the content Example cyclopentene ML-4 theoretical EXAMPLE 13 200parts of cyclopentene and 1,000 parts of toluene are introduced into theautoclave described in example 1. This is followed by the addition atroom temperature of 0.068 part of l-butene in the form of a 1 percentsolution in toluene, and then by the addition of 0.16 mMol of3,5-dich1oro-1 ,2-dinitro-benzene dissolved in 10 parts of toluene. 1.2mMols of WCl dissolved in 20 parts of toluene are then added, followedby cooling to 10" C. 1.8 mMols of aluminum triisobutyl dissolved in 15parts of toluene are then added at that temperature. After 3 hours,polymerization is interrupted by the ad dition of 10 parts ofethanolamine, and the polymer is precipitated in 4,000 parts of methanolcontaining 20 parts of 4-methyl-2,5-di-tert.butylphenol and dried in arecirculating air oven at C. The yield comprises 73 percent of thetheoretical. The product has a Mooney-viscosity of 84 and a trans-bondcontent of 94.1 percent.

If the same procedure is repeated in the absence of 1- butene, the yieldis 72 percent and the trans-bond content is 93.8 percent. The producthas a viscosity immeasurably in excess of 150 Mooney ML-4.

EXAMPLE 14 200 parts of cyclopentene and 1,000 parts of toluene areintroduced into the autoclave described in example 1. 0.016 parts ofl-butene in the form of a 1 percent solution in toluene are then sprayedin, followed by the addition of 0.20 mMols of 3,5-dichloro-l ,2-dinitrobenzene in the form of a 0.5 percent solution in toluene and thenby the addition of 1.6 mMols of WC] in solution in 20 parts of toluene.The product is then cooled to 8 C., after which 0.72 mMols of tintriethyl hydride in 30 parts of toluene are added. The temperature iskept at 5 C. by external cooling. After 3 hours, polymerization isstopped by the addition of 5 parts of tartaric acid, dissolved inmethanol; 0.6 parts of 3,3- dimethyl-5,5'-di-tert.-butyl-6,6'-dihydroxydiphenyl methane are added and the solution is introduced slowly inmeasured quantities into boiling water, stirred continuously in thepresence of steam. The resulting moist crumbs are dried in a dryingcabinet at 80C./50 mm Hg. The yield amounts to 79 percent, the Mooneyviscosity to 80 M1-4 and the trans-bond content to 94.2 percent. If thesame procedure is repeated in the absence of l-butene, substantially thesame yields and bond contents are obtained, although the Mooneyviscosity amounts to around 140.

EXAMPLE 15 50 parts of cyclopentene are introduced into a ml capacityflask which can be stirred magnetically. l mMol of tungsten tetra-allyland then 0.5 mMol of BCl are added after the contents of the flask havebeen cooled to --15 C. The temperature is kept at 5 C. by externalcooling. After 5 hours, the polymer is precipitated in 500 parts ofmethanol containing 5 parts of ethanolamine and 1 part of2,5-di-tert.-butyl-pcresol. The yield comprises 40 parts. The viscositycannot be measured. The gel content amounts to 21 percent, while thetrans-bond content of the soluble component amounts to 92.2 percent.

If the same procedure is repeated, and polymerization is modified by theaddition of 0.009 parts of propylene, dissolved in parts of toluene, aMooney viscosity of 42 M14 is obtained for a yield of 39 parts and atrans-bond content of 9 1 .8 percent.

We claim:

1. in the process for the ring opening polymerization of cycloolefinsdissolved in organic solvents in the presence of a metal-organic mixedcatalyst which is I. a mixture of (a) a compound of a metal of groupsIVa, Va and VIa of the periodic system and (b) a compound of the formulaleast one less than the maximum valency of Me and the sum of x, y and 2corresponds to the maximum valency of Me or II. a mixture of (a) anorganic compound of a metal of groups We: to Vla of the periodic systemand (b) Friedel-Crafts catalyst, the improvement which comprises adding0.001 to 1 percent by weight of l-olefin to the cycloolefin beforepolymerization.

2. The process of claim 1 wherein said cycloolefin is cyclopentene.

3. The process of claim 1 wherein dicyclopentadiene, norbomadiene ornorbornene is used as an additional monomer in an amount of from 0.05 to5 percent by weight.

4. The process of claim 1 wherein said l-olefin is ethylene, propylene,l-butene, l-pentene, 4-methyl-1- pentene or styrene.

5. The process of claim 1 wherein said F riedel-Crafts catalyst is WCL,BF WCL, MoCl WCl or Ta C1,.

2. The process of claim 1 wherein said cycloolefin is cyclopentene. 3.The process of claim 1 wherein dicyclopentadiene, norbornadiene ornorbornene is used as an additional monomer in an amount of from 0.05 to5 percent by weight.
 4. The process of claim 1 wherein said 1-olefin isethylene, propylene, 1-butene, 1-pentene, 4-methyl-1-pentene or styrene.5. The process of claim 1 wherein said Friedel-Crafts catalyst is WCl6,BF3, WCl4, MoCl5, WCl6, or Ta Cl5.